The present invention is directed to an anchor member securable within a borehole in a receiving material by a settable or hardenable mass. The anchor member includes an axially extending core member formed of metal with an axially extending connecting thread thereon. The portion of the core member inserted into the receiving material is enclosed in a jacket of a electrically non-conductive plastics material.
Anchor members of the type described above are used mainly in railroad construction for securing rails, carrying an electrical current, to a substructure formed of concrete. Initially, a settable hardenable mass in a premixed state or in separate compartments of a destructable cartridge is injected into a borehole and subsequently the anchor member is placed into the borehole. During the insertion of the anchor member, usually with a rotational motion, a mixing of the hardenable mass components as well as a uniform distribution of the mass takes place within the borehole. The attachment member is inserted into the borehole until its leading end in the installation direction reaches the base of the borehole.
In known anchor members of this type, for example as disclosed in DE-OS No. 33 20 429, the leading end of the jacket is shaped in the manner of a wedge-like or roof-like cutter extending transversely of the core member axis. With this type of leading end of the jacket, initially the anchor member contacts the base of the borehole at its radially outermost points. The jacket can be damaged or destroyed at its leading end, particularly when the anchor member is being installed with a turning or rotational action, so that the insulating effect of the jacket around the core member may not be complete.